Trailers configured to be towed behind automotive vehicles typically include trailer electrical systems that include lights, wiring and a trailer electrical plug. The lights are generally mounted on or near a rear portion of the trailers they are mounted on. The lights include left and right turn signal lights, and left and right taillights. Each light normally includes an incandescent lamp and a socket configured to receive the incandescent lamp. The wires extend from the light sockets to the trailer electrical plug. A standard type of plug used in such electrical systems is known as a "four-flat" trailer wiring plug and is configured to plug into a complementary vehicle electrical plug mounted on a tow vehicle. When joined together, the trailer and vehicle plugs connect tow vehicle electrical system wires to the trailer electrical system wires, which transmits power from vehicle lighting circuits to the trailer electrical system to illuminate the trailer lights.
Each trailer electrical plug typically includes four electrical connectors. One of these four connectors is connected to a chassis ground wire that connects to a chassis ground lead from each light through the trailer chassis. Another of the four connectors is connected to a wire that extends and connects to the left turn signal light. A third of the four connectors is connected to a wire that extends and connects to the right turn signal light. The remaining connector is connected to a wire that extends to both the left and right taillights.
The four connectors of the trailer plug generally include one female and three male connectors encased in a parallel disposition in a plastic jacket or casing. Similarly, the vehicle plug includes four connectors encased in a plastic jacket. However, the four connectors of the vehicle plug generally include one male and three female connectors to complement the one female and three male connectors of the trailer plug. The one female trailer plug connector and the one male vehicle plug connector are conventionally the chassis ground connection. The other three connectors are conventionally, in order from the ground connectors, the tail light connectors and the left and right turn signal light connectors. This convention insures that the correct contacts are made between taillight and turn signal light circuits whenever a trailer electrical system is connected to a tow vehicle electrical system.
Trailer electrical systems are also known to include circuit breakers. The circuit breakers are configured to open circuits that are shorted or supplied with an excessive amount of electrical current. The circuit breakers must then be reset before the circuit can be closed after a fault has been corrected. Some trailer electrical systems also include sensor lights that illuminate when a given circuit is closed and extinguish when the circuit is opened.
In the electrical arts, it is known to employ polymeric positive temperature coefficient resettable fuses (PTC devices) that use conductive-polymer technology to limit the flow of dangerously high current during fault conditions. These are solid-state devices configured to reset after a fault is cleared and power to the circuit is removed.
Also known in the electrical arts are bi-color light-emitting diodes (LED's), each of which includes two monochromatic light sources. Each monochromatic light source includes a tiny chip that generates a very narrow band of electromagnetic energy in the visible spectrum, i.e., colored light. The two chips are encased in a single epoxy lens, which may also be colored.
What is needed is a trailer electrical system circuit protection and fault indication system that is readily observable and understandable and that is self-resetting.